From 2002 to present day, the bird population has doubled from roughly 100,000 to 200,000. The bird population was decreasing extremely due to pollution and the salt levels used for food and medicine, however the flats have been on the road to recovery after the clean water act and the endangered species act was passed. Many species have come back to the area and reintroduced such as birds, fish, harbor seals, leopard sharks, and many other animals. In order to achieve this the government took two important steps; they opened up 50 ponds, some larger than 500 football fields, and they have restored around 2,000 acres of land to either ponds or marshes and have fixed the saline level in many areas as well. The species have been recovering faster than expected which is great news for the environment as those species that might have gone endangered are now beginning to thrive.
http://www.mercurynews.com/science/ci_29008935/san-francisco-bay-bird-populations-doubled-since-2003
http://www.mercurynews.com/science/ci_29008935/san-francisco-bay-bird-populations-doubled-since-2003